Hydropyrolysis of hydrocarbonaceous fuel at short reaction times

ABSTRACT

Coal or residual oil may be hydropyrolyzed at short reaction times to produce relatively high yields of methane and liquids and relatively low yield of coke. A bed of coke pellets, fluidized with a gas containing hydrogen, operates at 1100* to 1800* F and preferably at a pressure greater than 20 atmospheres. The coal or residual oil is fed to the bed and is heated practically instantaneously to the bed temperature, hydropyrolyzing to yield gaseous products and a coke product accreting upon the pellets. A fine solid is supplied to a space provided above the fluidized bed of coke pellets, the fine solid flowing at a temperature and rate to maintain the temperature of the fluidized bed substantially constant. The dimensions of the fluidized bed and space are such that the overall residence time of gaseous products of hydropyrolysis, including unreacted hydrogen, in the bed and space is less than 20 seconds. A residence time less than 5 seconds can be provided.

Unite Squires States Patent [1 1 Dec. 17, 1974 Arthur M. Squires, 245 W.104th St., New York, N.Y. 10025 Filed: Oct. 26, 1973 Appl. No.: 410,070

Related US. Application Data [63] Continuation of Ser. No. 167,686, July30, 1971, abandoned, which is a continuation-in-part of Ser. No.812,786, April 2, 1969, Pat. No. 3,597,327.

[76] Inventor:

52 US. Cl ..201/23,201/31,201/37,

208/127 511 int. Cl ..C10b49 /22 5s FieldofSearch ..201/31,21-23,

PEZZETS Primary ExaminerNorman Yudkoff Assistant ExaminerDavid EdwardsAttorney, Agent. or Firm-Abraham A. Saffitz 57 ABSTRACT Coal or residualoil may be hydropyrolyzed at short reaction times to produce relativelyhigh yields of methane and liquids and relatively low yield of coke. Abed of coke pellets, fluidized with a gas containing hydrogen, operatesat l100 to l800F and preferably at a pressure greater than 20atmospheres. The coal or residual oil is fed to the bed and is heatedpractically instantaneously to the bed temperature, hydropyrolyzing toyield gaseous products and a coke product accreting upon the pellets. Afine solid is supplied to a space provided above the fluidized bed ofcoke pellets, the fine solid flowing at a temperature and rate tomaintain the temperature of the fluidized bed substantially constant.The dimensions of the fluidized bed and space are such that the overallresidence time of gaseous products of hydropyrolysis, includingunreacted hydrogen, in the bed and space is less than 20 seconds. Aresidence time less than 5 seconds can be provided.

7 Claims, 3 Drawing Figures PATENTEB DEC] 7 I974 SHEET 2 0F 3 F/GZHYDROP YROLYSIS OF HYDROCARBONACEOUS FUEL AT SHORT REACTION TIMES 1969,and to issue as U.S. Pat. No. 3,597,327, on Aug.

BACKGROUND OF THE INVENTION My U.S. Pat. No. 3,437,561 discloses atechnique for hydrocarbonizing coal in an agglomerating fluidized bed,to form pellets of coke and a gas rich in methane.

US, Pat. No. 3,030,297 teaches the hydrogenation of coal in absence ofan added oil and of catalyst at a temperature between about 600 and1,000C, at a pressure of about 500 to 3,000 pounds per square inchgauge, at a total time of reaction for the coal-hydrogen mixture above300C of less than 2 minutes, and at a time of reaction above 600C ofless than one minute. The time of reaction above 600C is preferablybetween about 2 and seconds. In an example, this patent teaches theheating of a mixture of coal and hydrogen in a tubular preheater to 600Cin about 1 minute. Reaction is initiated in the preheater. The mixturepasses from the preheater to a reactor provided with a jacket fortemperature control. As a result of formation of methane in the reactor,the temperature of the mixture rises about 150 to 200C. Retention timein the reactor is also less than about 1 minute. Products were rapidlyquenched by spraying water into the stream .to reduce the temperature toaround 250C. Yield of a light aromatic liquid was 50 percent by weightof the coal fed (on a moistureand ash-free basis), conversion ofhydrogen was 55 percent, and yield of hydrocarbon gas was 6 standardcubic feet per pound of coal fed.

The technique disclosed in my U.S. Pat. No. 3,437,561 can beadvantageously employed to conduct substantially the process of theabove-described example from U.S. Pat. No. 3,030,297. To do this, thetotal reaction time prior to quench of hydrogenation products would besuitably limited, and the total heat content of hydrogen and coal fed tothe agglomerating bed of U.S. Pat. No. 3,437,561 would be adjusted tomatch the heat added to the mixture of hydrogen and coal in thepreheater of the example from U.S. Pat. No. 3,030,297. Better control ofthe operation is afforded using the technique of-U.S. Pat. No.3,437,561. In the example from U.S. Pat. No. 3,030,297, there is risk inpractical operation that too little heat will be added in the preheater,with the effect that insufficient reaction will occur in the reactor andthe desired temperature at the reactor outlet will not be attained. Onthe other hand, there is also risk that too much heat will be added inthe preheater, and the reaction in the reactor will be so vigorous thatthe desired temperature will be greatly exceeded and the reactorendangered. These dangers do not arise in operation of the agglomeratingbed of U.S. Pat. No. 3,437,561. Also, by the technique of 3,437,561,there is no necessity to provide tubular surface for transfer of heat toand from a mixture of coal and hydrogen; not only is such surfaceexpensive, but also it is subject to risk of fouling by deposits of cokewhich would mar its performance.

However, the range of operability of the technique disclosed in my U.S.Pat. No. 3,437,561 is narrow because the agglomerating bed was to beoperated adiabatically. The range of suitable variables such as hydrogenpressure, temperature, and coal feed rate was relatively narrow. I havefound that operation outside of this relatively narrow range ofvariables is frequently desirable to attain the full benefit of thesuperior yields of gas and liquid which short reaction times can afford.Sometimes, in order to sustain the temperature of the agglomerating bedat the desired level, more heat must be added than can conveniently beintroduced in form of sensible heat in the fluidizing gas. This is oftenthe case when conditions are selected for maximum production of a liquidproduct. If a large production of methane is achieved, sometimes heatmust be withdrawn from the agglomerating bed.

My aforementioned application, to become U.S. Pat. No. 3,597,327,teaches a procedure for supplying heat to or removing heat from anagglomerating fluidizedbed zone of the type disclosed in my U.S. Pat.No. 3,437,561. A superposed, contiguous fluidized-bed zone is providedcomprising a solid smaller in particle size than the coke pellets of theagglomerating-bed zone. The fluidizing-gas velocity in the superposedfluidized-bed zone is appreciably less than the velocity in theagglomerating zone. Heat can be supplied to or removed from theagglomerating zone by allowing heat to flow by conduction between thiszone and the superposed fluidized-bed zone.

If a short reaction time is desired, the procedure of U.S. Pat. No.3,597,327 has the drawback that the gas residence time in the superposedfluidized-bed zone of fine solid is necessarily rather long, because thefluidizing-gas velocity appropriate for the stationary fluidization of afine solid is relatively low.

' SUMMARY OF THE INVENTION The invention relates to an improved methodfor bydropyrolyzing coal or residual oil under conditions which areagglomerating with respect to the coke product and which give maximumyield of gas or liquid.

An object of the invention is to provide an improved process forconverting caking coals or residual oils into gaseous and liquidproducts and coke.

Another object is to provide processes to produce liquid fuels from coalor lighter liquids from heavy residual oils.

Another object is to provide processes yielding a methanerich gas andcoke starting from coal, including bituminous and subbituminous coalsand lignites, many of which are not ordinarily considered to be cakingcoals, or from fluid hydrocarbonaceous fuel such as residual oil,bitumen, pitch, tar, kerogen, and the like.

Another object is to provide processes to produce a synthetic fuel gasof pipeline grade according to U.S. standards for such a gas.

More specifically, the invention relates to an improved method forsupplying heat to (or removing heat from) a fluidized-bed zone in whichcoal or oil undergoes pyrolysis in presence of hydrogen, underconditions which are agglomerating with respect to the coke product, andat short residence times for the gaseous products of the hydropyrolysis.

According to the invention, there is provided a process forhydropyrolyzing a solid or liquid hydrocarbonaceous fuel at shortreaction times. A fluidized bed at a temperature between about 1 100 andl800F is provided, the bed comprising coke pellets larger than about'onesixty-fourth inch in size and displaying a range of diameters. The bedis fluidized with a gas containing hydrogen, preferably at a pressuregreater than 20 atmospheres. Solid or liquid hydrocarbonaceous fuel ischarged to the fluidized bed, and the solid product of thehydropyrolysis occurring within the bed accretes upon the coke pellets.A space is provided above the fluidized bed to receive gaseous productsof the hydropyrolysis including unreaeted'hydrogen, and the dimensionsof the fluidized bed and the superposed space is such that the residencetime of the gaseous products is lessthan about 20 seconds. A fine solid,preferably between about 50 and 100 microns in size and displaying arange of diameters, is supplied to the space, preferably near the upperlevel of the fluidized bed, at a temperature and rate of flow tomaintain the temperature of the fluidized bed substantially constant.Gaseous products and fine solid are removed from the top of thesuperposed space, and coke pellets are withdrawn from the fluidized bed.

I have been surprised to discover that there is an'effective transfer ofheat between the fine solid introduced into the superposed space and thefluidized bed of coke pellets, even though the gas velocity in the spacebe too high for the establishment therein of a stationary fluidized bed.I do not fully understand the relative importance of several mechanismsof heat transfer which appear to occur. Some fine solid falls onto theupper surface of the bed of coke pellets. This solid exchanges heat withthe coke, and then is reentrained by gas and carried back into thesuperposed space. Coke pellets are ejected from the agglomeratingfluidized bed into the superposed space, and the pellets exchange heatwith gas and fine solid in this space while the pellets fall back intothe bed. Downward currents of gas occur in the space, and such currentsexchange heat with the upper surface of the bed of coke pellets. Bywhatever mechanisms, the exchange of heat is effective in preventing thedevelopment of a large temperature difference between the bed of cokepellets and the superposed space. Addition of a'fine solid hotter thanthe bed of coke pellets serves to provide heat to the bed, and additionof a cooler solid serves to withdraw heat. By maintaining a relativelyhigh gas velocity in the superposed space, the residence time of gaseousproducts including unreacted hydrogen can be kept low. The velocity offluidizing gas in the agglomerating bed is advantageously between about5 and 25 feet per second, and the gas velocity in the superposed spaceis advantageously between about 4 and feet per second.

The term solid or liquid hydrocarbonaceous fuel as here used embraces,as a first category, solid fuels which when heated either exhibit asoftening tempera-' ture or begin to decompose with deformation and, asa second category, fuels normally liquid at room temperature and solidfuels which when heated exhibit a melting temperature and can thereafterbe pumped.

Suitable fuels of the first category for practice of the invention areto be found among bituminous and subbituminous coals and lignites,including many coals ordinarily considered non-caking when viewed inlight of conventional atmospheric-pressure coal-carbonizationprocedures. To use some of the non-caking coals or lignitessuccessfully, one must operate the process of the invention at a highpressure and provide for presence ofa high partial pressure of hydrogen.It is to be understood that bituminous and subbituminous coals andlignites may be altered by a partial carbonization or a partialoxidation or a reduction in the intrinsic moisture (as, for example, inthe drying of lignites by the Fleissner Process). Suitable fuels of thefirst category are also to be found among such altered coals andlignites, provided the altered material does not contain more than 9lweight percent carbon on a moistureand-ash-free basis and display ahydrogen-to-carbon ratio below 0.6.

Coal or other solid fuel for treatment by the process of the inventionis advantageously ground to a fineness substantially smaller thanIOO-mesh (US. Standard) before it is charged to the agglomeratingfluidized bed.

Fuels of the second category include petroleum fractions from thegas-oil range and heavier, but the greater practical interest lies inapplication of the instant invention to treatment of fuels of the secondcategory which are generally characterized by high specific gravity, lowhydrogen content, a significant aromatic content, and

' a Conradson carbon greater than about 1 percent, usually greater than2 percent. Examples of the latter fuels are residual fuel oils, crackedresidua, asphalts, asphalt fractions prepared from residua by solventextraction, heavy coker tars, coal tars, pitches, bitumens, carbonaceousmatter from tar sands, Gilsonite, kerogens, carbonaceous matter from oilshales, and the like. An artificial heavy oil may be prepared byhydrogenating coal at high pressure and at a temperature in the vicinityof 800 to 900F, either catalytically or non-catalytically, and filteringthe product from coal ash; such an artificial oil is also suitable as afuel of the second category.

The importance of a short reaction time for maximizing yields of methaneand useful liquid products is readily understood. If the reaction timeis too long, particularly at higher temperatures, hydrogenation andcrackng of the liquid products diminish their quantity and increase theyield of coke and to some degree of methane. At lower temperatures, thelight molecules produced by the initial disruption of the feed tend tobe chemically active toward reactions which polymerize these species toform a heavy, non-distillable liquid tar having little if any greatervalue than the feed. This is particularly the ease for a coal feed. Themolecular weight of individual chemical species in raw coal typicallyaverages in the neighborhood of 3,000 to 5,000; the molecular weight ofthe largest species in the coal may be no more than 10 times greaterthan the average. Deelder (PhD. thesis, Tech. Hogeschool, Eindhoven,Netherlands, 1966, NASA Accession No. N66-26774) has shown that theintitial step in the rapid pyrolysis of coal is a depolymerizationleading to formation of free radicals of relatively low molecularweight. Subsequently, heavy tar of an oligomerous character forms byvirtue of the polymerization of the monomeric units, the heavy tar oftencontaining species of molecular weight greatly exceeding that of anyspecies present in the initial coal. Generalized characteristics of thecoke residue (index of aromaticity, mean number of condensed rings,ratio of oxygen to carbon) resemble those of separated hydrocarbons,suggesting that much of the coke is a secondary product ofpolymerization reactions. Liquid yield from a pyrolysis of coal can bemaximized if the free radicals initially formed can be directed intoreaction paths leading to relatively stable light species and away frompaths leading to heavy tar species and coke. In general, the formerpaths are favored by higher temperature and higher partial pressure ofhydrogen. However, the higher the temperature the greater the risk thatcracking reactions will increase the yield of coke at expense of yieldof liquid, and so it is important that the reaction time be short ifliquid is desired. On the other hand, if a lower reaction temperatureshould be preferred, for example because of a preference for analiphatic liquid product versus the aromatic product provided at highertemperatures, it is important that reaction time be short to preventpolymerization reactions from occurring which would alter the liquidproduct to a heavy, non-distillable tar of relatively low value.

The instant invention may be practiced over a wide range of temperatureand pressure and over a range of reaction time preferably smaller thanseconds. in general, higher temperature favors production of methane andalight aromatic liquid. Lower temperature favors production of aparaffinic liquid. Higher pressure favors production of lighter liquids.Shorter times tend to give greater relative yield of liquid, and longertimes tend to give relatively more methane and more coke.

In the operation of the instant invention at-higher dropyrolysis may berelatively small. In such a case, the quantity of fine solid introducedinto the space above the agglomerating fluidized bed of coke pellets mayamount to several pounds of fine solid per cubic foot of the gaseousproducts. In this circumstance, the fine solid may form what I prefer tocall a fast fluidized bed in the aforementioned space. This is indistinction from the stationary" fluidized bed of conventionalfluidization art. I will now explain this distinction.

In a stationary fluidized bed, the fluidized solid remains in place, thebed displays a distinct upper surface, and the bed is characterized by arelatively continuous solid phase and a relatively discontinuous gasphase. The solid mainly occupies 'the so-called dense phase, and the gaspasses through the bed primarily in form of bubbles." For a fine solid,having a mean particle size between about 50 and 100 microns, thefluidization velocity appropriate for stationary fluidization isgenerally below about 2 feet per second.

If the fluidization velocity to a stationary fluidized bed is graduallyincreased, the density of the fluidized bed decreases, but the rate ofdecrease in density with increase in velocity is not marked. Ultimately,however, a critical velocity is abruptly reached at which the density ofthe bed drops sharply; the bed appears sud- .denly to thin out. Unlessthe space containing the bed is extremely tall, the gas will convey mostof the bed overhead and away from the space. This critical velocity maybe termed the dilute-phase transition velocity for zero transport.

If now the space be supplied at the bottom with gas at a velocitysomewhat greater than this transition velocity, and if particulate solidbe supplied to the bottom of the vessel at a definite rate, the solidwill in general be conveyed upward through the vessel and out at the topin dilute-phase transport. However, if the rate of supply of particulatesolid be gradually increased, at a critical rate of supply the inventoryof solid in the space will sharply increase. Dense-phase regions appear,the solid in these regions tending to stream downward at a highvelocity.

If the gas velocity is further increased, a critical velocity is againreached at which the inventory of solid drops, and the solid supplied tothe space is again conveyed upward in dilute-phase transport. Thiscritical velocity may be termed the dilute-phase transition velocity fortransport" at the rate of supply of solid to the space.

For a given rate of supply of solid to the bottom of a space, thefast-fluidized state is a convenient term to denote the condition in thespace when the prevailing gas velocity is greater than the dilute-phasetransition velocity for zero transport and less than the dilutephasetransition velocity for transport at the given rate of supply.

The fast fluidized bed is in commercial use for the calcining ofaluminum hydroxide to produce cell-grade alumina (see L. Reh, FluidizedBed Processing, Chem. Eng. Pr0gr., vol. '68, p. 58, February 1971; seealso U.S. Pat. No. 3,565,408). In this application, the supply of solidto the bottom of the reaction space is established by separating solidfrom gas leaving the top of the space and returning the separated solidto the bottom. An inventory of 5 to 10 pounds of solid per cubic foot ofreaction space can be achieved for alumina of 50 to microns fluidized atabout 10 feet per second.

No scientific study of the fast fluidized bed is yet available, but somefacts already appear clear. In contrast to the stationary fluidized bed,the fast fluidized bed exhibits no upper surface but substantially fillsthe space available. There is a marked gradient in solid density betweenthe bottom and top of the space, the density being greater at thebottom. The aforementioned inventory of 5 to l0 pounds per cubic foot isan average. The solid phase in the fast fluidized bed appears on thewhole to be the discontinuous phase, and the gas phase appears to be onthe whole continuous.

The solid phase appears generally to take the form of falling streamersand ribbons, while the gas appears to flow upward inbetween. The gasconveys solid upward, and much refluxing of the solid occurs in the fastfluidized bed.

Heat interchange between the space receiving gaseous products ofhydropyrolysis and the agglomerating fluidized bed of coke pellets isenhanced if the instant invention be operated to provide for existenceof a fast fluidized bed in the aforementioned space. As mentionedearlier, the quantity of fine solid introduced into this space may besufficient to establish the fastfluidized state therein. If not, arecirculation of solid separated from gas leaving this space mayadvantageously be provided, to increase the rate of supply of solid tothe bottom of the space.

If the temperatures of the bed of coke pellets and the superposed spacediffer too greatly, they may be brought closer together by providingmeans to circulate coke pellets from the bed into the space. Forexample, a vertical pipe or riser could be provided extending from nearthe top of the bed of coke pellets well into the space, transport gasbeing supplied to the bottom of the pipe to convey coke pellets upwardtherein.

Seed particles should be added to the bed of coke pellets to provide newparticles on which coke may accrete.

Successful operation of the process of the invention depends uponcommencing the operation with a suitable starter bed of solid, whichshould comproise a starter solid displaying a range of particle sizes,preferably at least five-fold, and with a smallest particle larger thanabout one sixty-fourth inch. The starter bed need not be carbonaceous, asolid suitable for use at high temperature and having a density betweenabout 80 and 150 pounds per cubic foot being generally satisfactory.

Quenching of the gaseous products of hydropyrolysis may be practiced byany of several known techniques, such as injecting water or scrubbingwith a tar maintained at an appropriate temperature.

An advantageous procedure for quenching the products is to establish afast fluidized bed of the same fine solid above the superposed space,this additional bed operating at a suitable temperature, for exampleabout 600 to 900F, and receiving the products. A restriction in area forgas flow would be provided between the superposed space and theadditional bed to hinder back- I flow of gas or solid. This arrangementallows for a particularly short reaction time, for example less than 5seconds.

The coke product of the invention may advantageously be gasifled byreaction with oxygen and steam, air and steam, air and combustionproducts or flue gas, air and carbon dioxide, or other such gasificationmedia. An advantageous gasification procedure would combine a stationaryfluidized bed of coke pellets and a superposed fast fluidized bed,operating at substantially the same velocity, to consume coke finesproduced as the coke pellets waste away and disintegrate. By operatingat a temperature between about l900 and 2100F, one may advantageouslyexploit the discovery of Godel (see my article in Science, vol. 169, p.821, Aug. 28, I970) that ash matter from substantially all coals becomessticky in this temperature range. As ash matter is released from thewasting away of the coke pellets, ash sticks to ash and forms loose,friable agglomerates. As the agglomerates grow, they reach a size toolarge to be buoyed in the fluidized bed of coke pellets, and they sink,to the bottomof this bed. This bottom is advantageously provided infrustoconicai form exhibiting an included angle of 60, with the smallerarea at the bottom, this area leading into a vertical pipe forconducting ash agglomerates away from the fluidized bed. A rotatinggrate may advantageously be provided at the bottom of the pipe todischarge ash agglomerates therefrom.

If operation of the invention calls for providing fine solid at atemperature greater than the temperature of the agglomerating fluidizedbed of coke pellets, the fine solid may advantageously be heated in afast fluidized bed by combustion of a fuel gas, sometimes advantageouslyfuel gas produced by the aforementioned gasification of coke product. I

BRIEF DESCRIPTION OF THE DRAWINGS The invention including various novelfeatures will be more fully understood by reference to the accompanyingdrawings and the following description of the operation of thealternatives illustrated therein:

FIG. 1 is schematic diagram of an embodiment of the invention fortreating coal.

FIG. 2 is a schematic diagram of an alternative embodiment generallycapable of affording an especially short time of reaction.

FIG. 3 is a schematic diagram illustrating how coke pellets resultingfrom the process of the invention may be gasified to produce a fuel gasor a synthesis gas. FIG. 3 also illustrates how this fuel gas, oranother fuel gas, may advantageously be used to heat a fine soid whichserves to carry heat to the hydropyrolysis step in FIG. 1 or FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference is now made to theschematic diagram of FIG. 1. Grinding means 2 grinds bituminous coalfrom line 1, preferably to a fineness such that substantially all of thecoal will pass through a IOO-mesh screen (US. Standard) and such thatabout percent will pass through a 200-mesh screen. Line 3 conveys theground coal to drying-and-heating means 4. Line 5 carries dried andheated coal from means 4 to lock system 6, which is supplied with a gasrich in hydrogen from line 7. Lock system 6 preferably has the formdisclosed in my co-pending application, filed simultaneously herewith,entitled Method and Apparatus for Transferring a Comminuted Solid from aLow Pressure into a Space Occupied by Gas at High Pressure. Coal passesvia a multiplicity of lines 8 and nozzles 9 into vessel 10. Forsimplicity of the drawing, only one line 8 and one nozzle 9 are shown.Vessel 10 houses agglomerating fluidized bed 11. Bed 11 comprises cokepellets larger than about one sixty-fourth inch in diameter andpreferably displaying at least a five-fold range in size. Bed 11 is, ingeneral, preferably at a pressure greater than about 20 atmospheres andat a temperature between about ll00 and l800F. Fluidizing gas rich inhydrogen is supplied to bed 11 via line 12. Coal entering bed ll vianozzle 9 is heated almost instantaneously to substantially the bedtemperature, and hydropyrolysis of the coal is initiated practicallyinstantaneously. Almost at once, the coal is split into a gaseousfraction and a sticky, semi-fluid residue. The latter is captured" by acoke pellet, sticking thereto to form a smear upon the surface of thepellet. Bed 11 serves as a dust trap" for the sticky initial pyrolysisresidue. Further reactions with hdyrogen convert the gaseous fractioninto lighter products and transform the sticky smear into dry coke withevolution of additional gases and vapors. The solid residue of thehydropyrolysis of the coal remains sticky for a time onlyon the order ofa second. Coke pellets are discharged from bed 11 via pipe 13, to keepthe inventory of coke pellets in bed 11 substantially constant. Gasesand vapors from bed 11 pass into zone 14. 'A fine pulverulent solid,preferably between about 50 and microns in average particle size, isintroduced into zone 14 via line 29. Line 29 preferably enters vessel 10approximately at the elevation of the upper surface of bed 11. The finesolid entering via line 29 is at a higher temperature than bed 1 1 ifthe overall chemical process which occurs in bed 11 is endothermic.Alternatively, the fine solid is at a lower temperature than bed 1 1 ifthe process in bed 1 1 is exothermic. The temperature and quantity offine solid passing through line 29 are variables providing a control onthe temperature of bed ll. Fine solid entering zone 14 from line 29quickly exchanges heat with gases and solids in zone 14. The solids inzone 14 comprise the fine solid, being conveyed upward, and also, in thelower elevations of zone 14, some coke pellets which have been ejectedupward into zone 14 from bed 11 and are falling back into bed 11. Thereis effective heat interchange between bed 11 and zone 14, and nosubstantial temperature gradient exists throughout vessel 10. Fine solidand gases and vapors leave vessel at the top via line 15, and solid andgas are separated in cyclone separator 16. Gases and vapors pass fromseparator 16 via line 17 to quench means 18, where these materials arequickly reduced in temperature. Means 18 may take any of several knownforms; e.g., a scrubbing column may be provided, with supply of ascrubbing oil entering the column at a temperature below the temperaturedesired for the quench. Quenched gases and vapors may advantageouslypass directly from quench means 18 via line 19 to a treating operation20, in which the materials are hydrotreated without prior cooling andcondensation of the vapors, as suggested for example in US. Pat. Nos.3,231,486 and 3,244,615. The treated products are delivered via line 21.Fine solid separated from gases and vapors in cyclone 16 passes downwardthrough standpipe 22 through solid-flow-control valve 25 and into riser27, which is supplied with conveying gas from line 26. The solid isconveyed upward in riser 27 into means 28 for heating or cooling thefine solid. The heated or cooled solid is returned from means 28 tovessel 10 via line 29, already mentioned. It will be understood that ifthe overall chemical process in bed 11 is exothermic, means 28 will coolthe solid; alternatively, if the process in bed 11 is endothermic, means28 will heat the solid. A supply of seed particles of coke is furnishedto bed 11 from line 52 via valve 53. The supply of seed should be at aparticle-number rate substantially equal to the particle-number rate ofwithdrawal of coke product from bed 11 via pipe 13. Make-up of finesolid may also be added as required from line 52 via valve 53.

It is desirable that the fine solid move upward through space 14 in thefast-fluidized state", as hereinbefore described. Sometimes the rate ofsupply of solid from line 29 to space 14 is sufficient to establish thefast-fluidized state inspace 14. If not, line 23 and valve 24 aredesirably furnished to circulate additional solid from standpipe 22 intospace 14 near its bottom. The advantage of providing for attainment ofthe fastfluidized state in space 14 is that heat exchange between thisspace and bed 11 is more effective, and the temperatures throughout bed11 and zone 14 are more uniform.

The fine solid is suitably a fine size of coke or a sand or an aluminaor an alumina-silicate or any of a wide 7 range of other solids.

EXAMPLE 9.7 carbon 5. 3 hydrogen 3.8 sulfur 9.9 oxygen 1.3 nitrogen 10.0ash The higher heating value of the coal is 12,700 British thermal unitsper pound (dry basis). The coal is dried and heated to 300F in means 4.Gas supplied in lines 7 and 12 is substantially pure hydrogen at anaverage temperature of 1,000F, and the total flow of hydrogen amounts to4,088.3 pound-moles per hour. Bed 11 operates at 1600F and atmospheres.Coke pellets in pipe 13 comprise 22,500 pounds per hour of coke and10,000 pounds per hour of ash. Gas and vapor in line 19 comprise 31,500pounds per hour of a light, distillablearomatic tar and 1,510pound-moles per hour of methane, along with 1,520 pound-moles per hourof unreacted hydrogen and minor amounts of CO CO, H20, H25, and NH3.

The coke pellets in bed 11 suitably range from about one-twelfth inch toabout one-half inch in diameter, and the -fluidizing-gas velocity issuitably 20 feet per second at the bottom of bed 11 and 15 at the top.The height of bed 1 1 is suitably 40 feet, to provide a gas residencetime on the order of 2.5 seconds. The gas velocity in zone 14 issuitably 7 feet per second. The height of zone 14 is also suitably 40feet, to provide a gas residence time on the order of 6 seconds. Thetotal gas residence time in vessel 10 and cyclone 16, prior to quench18, in less than 10 seconds.

The fine solid is alumina having a mean particle size of about 50microns and displaying an eight-fold range in size. Means 28 heats thealumina from 1600F to 2200F. The quantity of alumina flowing in riser 27and line 29 is 170,000 pounds per hour. This amounts to about 2.7 poundsper actual cubic foot of gaseous products of hydropyrolysis enteringzone 14 from bed 11, and is sufficient to establish the fast-fluidizedstate in zone 14.

Residual fuel oil or other solid or liquid hydrocarbonaceous fuel oftypes hereinbefore described could be substituted for the coal suppliedto vessel 10 via lines 8 and nozzles 9.

Turning now to FIG. 2, 1 describe an alternative embodiment capable ofproviding a shorter gas residence time. Coal or residual oil is chargedvia a multiplicity of lines 8 and nozzles 9 into vessel 10 housingagglomerating bed 11. The operation of bed 11 is substantially asdescribed earlier in connection with FIG. 1. A hydrogen-rich gas issupplied to bed 11 via line 12. Coke pellets are discharged from bed 11via pipe 13. Gases and vapors from bed 11 pass into zone 31. 1f theoverall chemical process occurring in bed 11 is exothermic, a relativelycolder fine solid is admitted to zone 31 from line 44 via valve 45. Ifthe process in bed 11 is endothermic, a relatively hotter fine solid isadmitted to zone 31 from line 51. Zone 31 and bed 11 operate atsubstantially the same temperature, the fine solid entering zone 31 fromline 44 or line 51 quickly exchanging heat with matter in zone 31 andapproaching this matter in temperature. The solid entering zone 31 isconveyed by gases and vapors through grid plate 32 and into zone 33,which operates at a temperature preferably between about 600 and 900Fand which serves to v quench the gases and vapors rising from zone 31.Zone 33 preferably operates as a fast fluidized bed. Fine solidaccompanies gases and vapors leaving zone 33 in line 34, and the solidis separated therefrom by cyclone separator 35. Gases and vapors pass totreating means 20 and leave the system via line 21. Solid from cyclone35 passes downward in standpipe 36 via valve 39 into riser 41. Riser 41is supplied with conveying gas from line 40, and solid from valve 39 isconveyed in riser 41 into cooling means 42, where the solid is cooled toa temperature preferably about 100 below the temperature of zone 33.Solid is returned from cooling means 42 to zone 33 via line 43. If theprocess in bed 11 is exothermic,-solid at substantially the temperatureof zone 33 is passed from standpipe 36 into zone 31 via line 44 andvalve 45. If the process in bed 11 is endothermic, line 46 is providedto convey solid via valve 47 into riser 49. Riser 49 is supplied withconveying gas from line 48, and solid from valve 47 is conveyed'in riser49 into heating means 50. Solid heated to a temperature greater thanthat in bed 11 is returned from means 50 to zone 31 via line 51. If theflow to fine solid from zone 31 and line 43 is insufficient to establishthe fastfluidized state in zone 33, line 37 and valve 38 areadvantageously provided to recirculate additional fine solid fromstandpipe 36 into zone 33. Line 52 and valve 53 are provided for supplyof seed particles of coke.

The embodiment of FIG. 2 is advantageous if an especially short gasresidence time is desired. For example, suppose the height of bed 11 is30 feet,with velocities of 20 feet per second at bottom and 15 at top,to provide a gas residence time on the order of 1.7 seconds. Zone 31might be 20 feet in height with a velocity of 7 feet per second, toprovide a gas residence time on the order of 3 seconds. The overall gasresidence time is thus less than seconds.

FIG. 3 depicts schematically an advantageous arrangement for heatingfine solid. The arrangement may be used for means 28 in FIG. 1, whenmeans 28 is intended for heating of fine solid.

Coke pellets made from coal by the process of FIG. 1 are introduced frompipe 13 into vessel 60, which operates at substantially the samepressure as vessel of FIG. 1. The coke pellets fall to the bottom ofvessel 60 to form fluidized bed 61. Gasification medium is introducedinto bed 61 from a multiplicity of substantially horizontal inlet pipes63 penetrating frusto-conical segment 64 of the walls of vessel 60. Theincluded angle of segment 64 is preferably about 60. The gasificationmedium may be steam and oxygen, if a gas comprising primarily hydrogenand carbon monoxide is desired. The gasification medium may be steam andair (or recycled combustion products and'air) if a fuel gas is desired.The temperature and composition of the gasification medium arepreferably adjusted so that the temperature of bed 61 is between about1900 and 2100F. The coke pellets react with the gasiiication medium toform a mixture of CH H CO, H 0, and CO together with N if thegasification medium includes air. The H CO, and H 0 can stand to oneanother in substantially the equilibrium relationship for reaction ofsteam with carbon if vessel 60 is made adequate in size. As coke .isconsumed from the coke pellets, ash matter is released. At the specifiedtemperature, ash matter of substantially all coals is sticky. Ash sticksto ash, not to coke; and as ash matter is released, ash agglomeratesform. when an agglomerate grows too large to be fluidized at thevelocity prevailing in bed 61 (suitably about IO feet per second), theagglomerate sinks to the bottom of bed 61 and enters zone 66in thestraight-sided section 65 of vessel 60. Zone 66 is a gravitating bed ofash agglomerates, the discharge of agglomerates from zone 66 beinggoverned by rotating grate 67, which is provided with a suitable drive68. Ash agglomerates drop into water pool 70 housed in chamber 69. Wateris furnished to pool from line 71. Ash and water are let down to theatmosphere through line 72, valves 73 and 75, lock chamber 74, and-line76. As coke pellets are consumed in bed 61, coke dust is generated whichenters zone 62 along with gasiiication-products. Zone 62 is a fastfluidized bed, established by the circulation of coke dust through line77 into cyclone separator 78, and thence into standpipe 79 and throughvalve 80 back into the bottom of zone 62. Fuel gas from cyclone 81 iscooled and desulfurized in means 82, preferably according to theteachings of my US. Pat. No. 3,402,998 for use of half-calcineddolomite, [Ca- COyl-MgO], to absorb H S from the fuel gas at atemperature slightly below the temperature at which CaCO has anequilibrium decomposition temperature equal to the partial pressure ofCO in the fuel gas. The desulfurized gas is delivered via line 83. Ifmore gas is desired than can be produced from the available cokepellets, raw coal may also be fed along with the coke pellets to vessel60. The raw coal may suitably be crushed to smaller than three-fourthsinch.

A portion of the desulfurized gas is used in FIG. 3 as a fuel in vessel85 to heat fine solid from line 27 of FIG. 1. Vessel 85 houses fastfluidized bed 86 and operates at substantially the same pressure asvessel 10 of FIG. 1. Fine solid is supplied to bed 86 from line 27. Fuelgas is supplied from line 84 via nozzles 87. (Alternatively, ifpreferred, another fuel gas might be used, including a fuel gasrecovered from products in line 21 of FIG. 1.) Combustion air issupplied at the bottom of bed 86 from line 88 in an amount insufficientfor complete combustion of the fuel, and additional air, sufficient tocomplete the combustion, is added from line 89 at an elevation on theorder of 10 feet above the bottom of bed 86. Combustion products andsolid leave vessel 86 via line 90 and are separated in cyclone separator91.

Combustion products leave via line 92, and solid moves downward instandpipe 93. A portion of the sold is returned to vessel 10 of FIG. 1via valve 96 and line 29. Another portion of the solid is returned nearthe bottom of bed 86 via line 94 and valve 95.

Vessel 85 may advantageously work in cooperation with a gas-turbinepower plant (not shown in FIG. 3). Air to lines 88 and 89 may besupplied from the air compressor of the gas turbine, or from another aircompressor of the axial-flow type commonly used in large industrial gasturbines. Combustion products from line 92 may be expanded in theexpansion turbine of the gas-turbine power plant.

If air is used in the gasifcation medium supplied in lines 63 to vessel60, the fuel gas in line 83 may advantageously be used to tire agas-turbine power plant (not shown in FIG. 3). If oxygen is used in thegasification medium, gases in line 83 may advantageously be used toprepare hydrogen for supply in lines 7 and 12 to vessel 10 of FIG. 1.Hydrogen for lines 7 and 12 may also be manufactured by reformingmethane in products in line 21 of FIG. 1.

I do not wish my invention to be limited to the particular embodimentsillustrated in the drawings and described above in detail. It will beunderstood that grid plate 32 of FIG. 2 may be replaced by other meansproviding for a restriction in area for gas flow to hinder the backflowof gas or solid from zone 33 to zone 31. Heating step 28 of FIG. 1 mightbe used to calcine dolomite,

and the pressure and temperature in vessel 10 might be chosen so thatcalcined dolomite supplied via line 29 to a fast fluidized bed occupyingzone 14 will recarbonate with production of heat in zone 14, either byabsorbing CO from gaseous products of hydropyrolysis entering zone 14from bed 11, or by absorbing CO from a gas containing CO or CO and Hintroduced into zone 14 from line 52 via valve 53. Other arrangementswill be recognized by those skilled in the art, as well as otherpurposes which the invention can advantageously serve.

I claim: 1. A process for hydropyrolyzing a solid or liquidhydrocarbonaceous fuel at short reaction times, comprismg:

providing a fluidized bed at a temperature between about 1 100 and 1800F and at a pressure greater than about 20 atmospheres, said fluidizedbed comprising coke pellets larger than about one sixtyfourth inch anddisplaying at least a substantially five-fold range in diameter;

supplying fluidizing gas to said bed at a superficial velocity greaterthan about 5 feet per second, said gas containing hydrogen;

charging a solid or liquid hydrocarbonaceous fuel to said fluidized bed,the solid product of the hydropyrolysis of said fuel within said bedaccreting upon said coke pellets;

providing a space situated above said fluidized bed to receive gaseousproducts of said hydropyrolysis including unreacted hydrogen, thedimension of said bed and said space being such that the residence ofsaid gaseous products in said bed and said space is less than aboutseconds, the diameter of said space being such that the superficialvelocity of said gaseous products in said space is greater than about 4feet per second;

supplying solid particles substantially smaller than l00 microns to saidspace at a temperature and rate of flow to maintain said temperature ofsaid fluidized bed substantially constant, said rate of flow beingsufficient to establish the fast-fluidized state in said space;

withdrawing said gaseous products and said solid particles from the topof said space; and,

withdrawing coke pellets from said fluidized bed.

2. The process of claim 1 including the following additional steps:

providing a second space situated above said first space situated abovesaid fluidized bed, said gaseous products and said solid particlessupplied to said first space being allowed to pass from said first spaceinto said second space, a restriction in area for flow being interposedbetween said two spaces to hinder backflow of gas or solid from saidsecond space to said first space; and,

withdrawing gas and solid at the top of said second space, separatingsolid from said gas by a syclone, cooling at least a portion of saidseparated solid and returning said portion to said second space tomaintain a temperature in said second space between about 600 and 900 F.3. The process of claim 2 in which said dimensions are such that saidresidence time is less than about 5 seconds.

4. The process of claim 1 in which at least a portion of the carboncontained in at least a portion of said coke pellets withdrawn from saidfluidized bed is gasified by a gasification medium selected from thegroup consisting of oxygen, air, steam, carbon dioxide, and flue gas ina second fluidized bed of said coke pellets operating at about l900 to2100 F, fine particles containing carbon being produced in said secondfluidized bed by the wastage of said coke pellets undergoinggasification, and including the step of establishing a fast fluidizedbed of said fine particles containing carbon in a zone above said secondfluidized bed by separating said fine particles from gaseous products ofgasification leaving the top of said zone and recirculating saidseparated fine particles to substantially the bottom of said zone.

5. A process for hydropyrolyzing a solid or liquid hydrocarbonaceousfuel at short reaction times, comprisproviding a fluidized bed at atemperature between about 1 and l800 F and at a pressure greater thanabout 20 atmospheres, said fluidized bed comprising coke pellets largerthan about one sixtyfourth inch and displaying at least a substantiallyfive-fold range in diameter;

supplying fluidizing gas to said bed at a superficial velocity greaterthan about 5 feet per second, said gas containing hydrogen;

charging a solid or liquid hydrocarbonaceous fuel to said fluidized bed,the solid product of the hydropyrolysis of said fuel within said bedaccreting upon said coke pellets;

providing a space situated above said fluidized bed to receive gaseousproducts of said hydropyrolysis including unreacted hydrogen, thedimensions of said bed and said space being such that the residence timeof said gaseous products in said bed and said space is less than about10 seconds, the diameter of said space being such that the superficialvelocity of said gaseous products in said space is greater than about 4feet per second;

supplying solid particles substantially smaller than lOO microns to saidspace at a temperature greater than said temperature of said fluidizedbed and at a rate of flow to maintain said temperature of said fluidizedbed substantially constant, said rate of flow being sufficient toestablish the fast-fluidized state in said space; withdrawing saidgaseous products and said solid particles from the top of said space;and, withdrawing coke pellets from said fluidized bed. 6. The process ofclaim 5 including the following additional steps:

providing a second space situated above said first space situated abovesaid fluidized bed, said gaseous products and said solid particlessupplied to said first space being allowed to pass from said first spaceinto said secondvspace, a restriction in area for flow being interposedbetween said two spaces to hinder backflow of gas or solid from saidsecond space to said first space; and, withdrawing gas and solid at thetop of said second space, separating solid from said gas by a cyclone,cooling at least a portion of said separated solid and returning saidportion to said second space to maintain a temperature in said secondspace between about 600 and 900 F. 7. The process of claim 6 in whichsaid dimensions are such that said residence time is less than about 5seconds.

1. A PROCESS FOR HYDROPYROLYZING A SOLID OR LIQUID HYDROCARBONACEOUSFUEL AT SHORT REACTION TIMES, COMPRISING: PROVIDING A FLUIDIZED BED AT ATEMPERATURE BETWEEN ABOUT 1100* AND 1800*F. AND AT A PRESSURE GREATERTHAN ABOUT 20 ATMOSPHERES, SAID FLUIDIZED BED COMPRISING COKE PELLETSLARGER THAN ABOUT ONE SIXTY-FOURTH INCH AND DISPLAYING AT LEAST ASUBSTANTIALLY FIVE-FOLD RANGE IN DIAMETER; SUPPLYING FLUIDIZING GAS TOSAID BED AT A SUPERFICIAL VELOCITY GREATER THAN ABOUT 5 FEET PER SECOND,SAID GAS CONTAINING HYDROGEN; CHARGING A SOLID OR LIQUIDHYDROCARBONACEOUS FUEL TO SAID FLUIDIZED BED, THE SOLID PRODUCT OF THEHYDROPYROLYSIS OF SAID FUEL WITHIN SAID ACCRETING UPON SAID COKEPELLETS; PROVIDING A SPACE SITUATED ABOVE SAID FLUIDIZED BED TO RECEIVEGASEOUS PRODUCTS OF SAID HYDROPYROLYSIS INCLUDING UNREACTED HYDROGEN,THE DIMENSION OF SAID BED AND SAID SPACE BEING SUCH THAT THE RESIDENCEOF SAID GASEOUS PRODUCTS IN SAID BED AND SAID SPACE IS LESS THAN ABOUT10 SECONDS, THE DIAMETER OF SAID SPACE BEING SUCH THAT THE SUPERFICIALVELOCITY OF SAID GASEOUS PRODUCTS IN SAID SPACE IS GREATER THAN ABOUT 4FEET PER SECOND; SUPPLYING SOLID PARTICLES SUBSTANTIALLY SMALLER THAN100 MICRONS TO SAID SPACE AT A TEMPERATURE AND RATE OF FLOW TO MAINTAINSAID TEMPERATURE OF SAID FLUIDIZED BED SUBSTANTIALLY CONSTANT, SAID RATEOF FLOW BEING SUFFICIENT TO ESTABLISH THE FAST-FLUIDIZED STATE IN SAIDSPACE; WITHDRAWING SAID GASEOUS PRODUCTS AND SAID SOLID PARTICLES FROMTHE TOP OF SAID SPACE; AND, WITHDRAWING COKE PELLETS FROM SAID FLUIDIZEDBED.
 2. The process of claim 1 including the following additional steps:providing a second space situated above said first space situated abovesaid fluidized bed, said gaseous products and said solid particlessupplied to said first space being allowed to pass from said first spaceinto said second space, a restriction in area for flow being interposedbetween said two spaces to hinder backflow of gas or solid from saidsecond space to said first space; and, withdrawing gas and solid at thetop of said second space, separating solid from said gas by a syclone,cooling at least a portion of said separated solid and returning saidportion to said second space to maintain a temperature in said secondspace between about 600* and 900* F.
 3. The process of claim 2 in whichsaid dimensions are such that said residence time is less than about 5seconds.
 4. The process of claim 1 in which at least a portion of thecarbon contained in at least a portion of said coke pellets withdrawnfrom said fluidized bed is gasified by a gasification medium selectedfrom the group consisting of oxygen, air, steam, carbon dioxide, andflue gas in a second fluidized bed of said coke pellets operating atabout 1900* to 2100* F, fine particles containing carbon being producedin said second fluidized bed by the wastage of said coke pelletsundergoing gasification, and including the step of establishing a fastfluidized bed of said fine particles containing carbon in a zone abovesaid second fluidized bed by separating said fine particles from gaseousproducts of gasification leaving the top of said zone and recirculatingsaid separated fine particles to substantially the bottom of said zone.5. A process for hydropyrolyzing a solid or liquid hydrocarbonaceousfuel at short reaction times, comprising: providing a fluidized bed at atemperature between about 1100* and 1800* F and at a pressure greaterthan about 20 atmospheres, said fluidized bed comprising coke pelletslarger than about one sixty-fourth inch and displaying at least asubstantially five-fold range in diameter; supplying fluidizing gas tosaid bed at a superficial velocity greater than about 5 feet per second,said gas containing hydrogen; charging a solid or liquidhydrocarbonaceous fuel to said fluidized bed, the solid product of thehydropyrolysis of said fuel within said bed accreting upon said cokepellets; providing a space situated above said fluidized bed to receivegaseous products of said hydropyrolysis including unreacted hydrogen,the dimensions of said bed and said space being such that the residencetime of said gaseous products in said bed and said space is less thanabout 10 seconds, the diameter of said space being such that thesuperficial velocity of said gaseous products in said space is greaterthan about 4 feet per second; supplying solid particles substantiallysmaller than 100 microns to said space at a temperature greater thansaid temperature of said fluidized bed and at a rate of flow to maintainsaid temperature of said fluidized bed substantially constant, said rateof flow being sufficient to establish the fast-fluidized state in saidspace; withdrawing said gaseous products and said solid particles fromthe top of said space; and, withdrawing coke pellets from said fluidizedbed.
 6. The process of claim 5 including the following additional steps:providing a second space situated above said first space situated abovesaid fluidized bed, said gaseous products and said solid particlessupplied to said first space being allowed to pass from said first spaceinto said second space, a restriction in area for flow being interposedbetween said two spaces to hinder backflow of gas or solid from saidsecond space to said first space; and, withdrawing gas and solid at thetop of said second space, separating solid from said gas by a cyclone,cooling at least a portion of said separated solid and returning saidportion to said second space to maintain a temperature in said secondspace between about 600* and 900* F.
 7. The process of claim 6 in whichsaid dimensions are such that said residence time is less than about 5seconds.